Notes from ISO-NE’s peak last night:

- ISO-NE called a Capacity Scarcity Condition (CSC). This is the margin call for capacity resources. This is the 6th since 2018, 3rd since 2024.

- CSCs are called when reserve rates rise above a set threshold. Last night it was $1000/MWh

- Actual spot prices were low—$1000/MWh for much of the peak, $1500/MWh at 5:40 PM, driven exclusively by reserve costs. Those prices aren’t high enough to justify building new peak resource.

- The day-ahead energy market cleared ~1 GW short on energy during the peak.

- Without BTM solar, the peak would have been 2.5 GW higher…and 3 hours earlier.

- ISO-NE’s peak forecast the day before was pretty dead-on.

- During the peak proper, only oil generation rose in output. Gas use was flat—I think maxed out at the pipeline. Imports from NYISO and Quebec were also flat—I think also maxed

- ISO-NE’s energy market doesn’t track batteries. No way to tell what BESS did at the moment.

- ISO-NE recently beefed up their credit requirements for power plants with Capacity Supply Auctions. They fear that in events just like this, power plants will miss their cue and pay so much in penalties that they go insolvent.

- …we’ll see if they’re right to worry soon.